Hydraulic jolt machine



H. E. FELLOWS 2,198,078 HYDRAUIJIC JOLT MACHINE Filed July 5, 1938 2 SheetsSheet 1 s mvzsmoR 372014222, vmeml ATTORNEY.

(.Apfil23,1940.

2 Sheets-Sheet 2 49 m. in?

VIII/Ill! INVENTOR.

' We, awq mwaawvmmw ATToRNEY H. E. FELLOWS 2.198.078

HYDRAULIC JOLT MACHINE Filed July 5, 1938 Patented Apr. 23, 1940 PATENT OFFICE- 2,198,078 HYDRAULIC 'JoL'r MACHINE Harrison E. Fellows, Wauwatosa, Wis., assignor to Milwaukee Foundry Equipment Company, Milwaukee, Wis., a corporation of Wisconsin Application July 5, 1938, Serial No. 217,479

5 Claims.

This invention relates to improvements in hydraulic jolt machines, and more particularly to a foundry jolt machine wherein the reciprocatory parts are hydraulically actuated.

5 :Jolt machines of .the ordinary type are usually arranged to impart a rapid reciprocating movement to amoldingfiask to initially pack the molding sand around the pattern within the flask before the sand is'subjected to the final squeeze and the removal of the pattern from the sand and flask. Compressed air has heretofore been used to reciprocate the machine parts, but compressed airis an expensive motivating medium-and is not always available.

It is, therefore, the primary object of the present invention to provide a jolt machine wherein the parts are reciprocated through the use of a liquid; such as oil, circulated in a closed circuit without material waste or loss, whereby the maand the machine is adapted for operation where absuitable supply of compressed air is not availa le.

If, (in 'a :jolt machine, oil for the motivating medium were to be handled in the standard manner indicated in other hydraulic mechanisms, it would seem to be proper to simultaneously control oil inlet and oil exhaust ,ports of the oil work chamber of the machine, Then, on the descent strokes of the piston the chamber and ducts would completely-exhaust their oil through theexhaust port and when the exhaust .port was closed and the inletport opened for the next cycle of operation it would be necessary for the ducts and :chamber to fill with oil before movement of the piston occurred. As applied to a jolt machine this would mean that there would be an unduly prolonged dwell of the piston and table at the lower end of each stroke, rendering impractical.

Aspecific object. of the present invention is to overcome the above objection by so handling and regulating the flowof oil that only, the exhaust port ofthe system is controlled whereby the work chamber-and ducts are always kept filled with oil so that reciprocation of the piston in opposite directions occurs without delay, due "to the constant presenceof oil there adjacent to perform lifting work. v '3- A further object of the invention is to provide 'iahydraulic jolt machine wherein the oil pump, when it is not pumping oil for work purposes, freely by-passes oil from the open inlet port through the open exhaustportand when mot chine motivating medium expense is minimized,

operation of the machine extremely .slow andis desired-the exhaust port is closed and oil from the pump, in addition to that continuously in the work chamber and ducts, performs its lifting duties.

A further object of the invention is to provide a hydraulic jolt machine wherein the valve controlled exhaustflf-port of the oil systemis so ar ranged that it will only accommodate the amount of oil delivered through theinlet port by the pump and the normal piston displacement, but will not exhaust or draw oil away from the work chamber and communicating duct, whereby the work chamber always contains an adequate amountof oil.

A further object of the invention is to provide a hydraulic jolt machine wherein the diameter of the work piston bears a directand predetermined relationship to the delivery capacity of the pump and to the diameter of theexhaust port.

. A further object of the invention is to provide a hydraulic jolt machine which is of very simple construction, which is easy to operate and control, which israpid and efiicient and economical in'its'operation, which is strong and durable, and which is well adapted for With ,the above and. other objects in view the invention consists of the improved hydraulic jolt machine, and its parts and combinations as set forth in the claims, and all equivalents thereof. In the accompanying drawings in which the same reference characters indicate the same parts in all of the views:

Fig.1 is a vertical sectional, view of the improved hydraulic jolt'machine with a schematic showing of the motor, pump and main control valve associated with the machine;

Fig. 2 is a horizontal sectional view of the machine taken onthe irregular line 2-2 of Fig. 1;

Fig. 3 is a horizontal sectional View taken on line 3' -3 of Fig. '1; m 1 .Fig. 4 is an enlarged, fragmentary detail sectional view of the inlet-and exhaust ports of the machine and thevalve for said latter port; and

Fig 5 is a detailsectional view taken on line 5-5 of.Fig. 4.

Referring now more particularly to the drawings, it will appear that themachine is mounted upon a substantially annular, hollow based on the top of which is supported a stationary cylinder 9 within which a guide piston in is adapted'to be vertically reciprocated. The upper end of the guide piston is formed with an integral, horizontal table H I. on which a molding flask v(not shown) is adapted to be positioned.

; The guide piston lllsis actuated'bythe imthepurposes set forth. 25

proved hydraulicjolting mechanism which is of the essence of the present invention. Within the lower recessed portion of the guide piston I0 there is secured a downwardly projecting striker pad l2 having a surface to engage the enlarged head of a jolt piston l3. Said jolt piston is slidably mounted vertically in the bore M of a body member l5 of the machine. The machine also includes a horizontal and radial body portion l6 whose inner end is integral with the lower end of the body member duct or chamber inner end ll of which the lower end of the jolt piston |3 extends, when in lowered position.

The horizontal and radial body portion 6 of the machine merges, at its outer'end, into the lower portion of a vertical boss portion I8 which has a bore H. The lower into the enlarged outer end I?" of the duct l1 and slidab-ly accommodates a jolt valve 20. Said jolt valve is of cylindrical formation and is provided with a pair of vents 2| so that fluid pressure on opposite ends or faces of the valve may be equalized. The lower end of a valve stem 22 is secured to said valve and said valve stem extends vertically upwardly through the bore of the boss l8 and also through a stufiing box 23 and a gland 24 at the upper end of said boss.

The outer end of the body portion 6 has a fluid inlet port 25 opening into the enlarged end ll" of the duct l1, and a fluid inlet pipe 26, extending from the outlet port of a three-way control valve 2'1, communicates with said inlet port 25. Within the lower portion of said body portion l6 there is also a liquid exhaust port 28 registering with the portion H" of the duct l7 and adapted to be controlled by said jolt valve 20.

A tubular connection 29 leads from said exhaust port 28 and enters one side of the reservoir of a high pressure oil pump 30. The pump is actuated by a suitable motor 3|, through a driving belt 32, and from the pressure side of the pump a pressure line or tubular connection 33 extends to an inlet port of the main control valve 21. By means of a tubular connection 34 between another port of said valve 21 and a port in said pump, oil may be by-passed when the pump is operating and when the valve 2"! is manipulated to prevent oil flow through the fluid inlet pipe 26. This latter contingency occurs when the jolt machine is idling.

It should be observed that the jolt valve 20 does not control the liquid inlet port 25, but only controls the liquid exhaust port 28. Also the size of the exhaust port 28 is such that it can only accommodate the amount of oil delivered through the inlet port 25 and normal piston displacement and cannot handle any oil in excess of such amount when the pump and valve Z'Iare operating to deliver oil under pressure through the port 25. The diameter of the jolt piston l3 also bears a direct and predetermined relationship to the delivery capacity of the pump and to the size of the exhaust port 28.

Aflixed to one side of the jolt table II is a bracket 35 to which the upper end of a reciprocable rod 36 is adjustably secured. The lower end portion of said rod is threaded into the upper end of a clevis 31 and is secured thereto against rotation by a cotter pin 38 which extends through slots in the upper side walls of the clevis. Within the clevis and having free movement or play as between the lower and intermediate walls 39 and 48 thereof, is a cylindrical nut 4| secured to the upper end portion of the valve |5 and having a horizontal therein, into the enlarged end' of said bore opens rod 22. By virtue of the adjustments of the member 36 relative to the bracket 35 and clevis 31 the amount of movement of the valve 20 can be regulated and controlled. Also, because of the free movement or play of the nut 4| within the clevis only a small portion of the movement of the table I is utilized for the transmission of motion to the valve rod 22 for actuation of the vjolt valve 20.

The operation of the improved hydraulic jolt machine is as follows: The main control valve 21 is operated to open the inlet line 26 and the motor and pump are set into operation. Oil under pressure, and at a fixed volume, is delivered by the pumpthrough said inlet line 26 into the port 25 from whence it flows in the enlargement I1" around the jolt valve 20 which is in closed or lowered position. The oil thus admitted fills the duct I7 and exerts lifting force against the bottom of the jolt piston I3. The jolt piston and parts carried thereby then rise at a speedcommensurate with the pistons displacement'of {the pump capacity. The piston engages the striker pad l2 and elevates the guide piston l0 and the table The initial elevation of said members is substantially the same as the-amount of play in the clevis 31 with relation to the movementof the nut 4| thereon, said clevis being-raised from the full line position of Fig. 1 to a positio'nwhere in the lower wall 39 of the clevis will engage the nut 4| and thereafter exert a lifting effect on the valve stem 22. The table and piston |3 move upwardly slightly beyond the position described, and this additional rise causes the jolt valve 20 to be lifted sufiicientlytoppenvthe oil exhaust port 28. The oil under pressure'is then free to exhaust from the duct I! to the pump via the port 28 and pipe 29. The pressure in the pipe 29 is at atmospheric pressure. Thepump continues in operation, but due to the size of the exhaust port 28 new oil pumped intothe ma-' chine is immediately exhausted throughsaidport 28 without influencing the supply or pressure within the duct l7 and acting on the piston l3. At this stage there is not sufiicient pressure below the piston I3 to support it, together with the table and load thereon. Hence the table anda'ssociated parts drop rapidly due togr'avity and the vacuum within the chambers '(particularly that below the guide piston) developed during-the up-stroke of the parts. This vacuum'condition causes descent of the parts at a greater rate" of speed than would be the case if gravitywas the only factor. I

As the table and pistons descend, the nut' 4| has a predetermined amount of free movement within the clevis 31 and thereafter it is engaged by the rod 36 so-that a downward'push posed on the valve stem 22 tolower-and seat the jolt valve 20 and thereby close the exhaust port 28. As long as the valve 27 is positioned to allow flow through the pipe 26 and the pu'r'np is in operation the cycle will repeat. It should be observed that this operation results in very rapid reciprocations of the table and flask thereon;- The movements are so synchronized that on each table up-stroke, at the proper time, the jolt valve is raised or opened, and on each table down-' stroke the jolt valve is closed. 1 r.

From the foregoing description it will be seen that the improved hydraulic jolt machine'is' of simple and novel construction, and is well'adapt-.: ed. for the purposes described. I

What is claimed as the invention is: .11:

1. A molding machine, comprisinga unitary ing a liquid duct therein opening adjacent said reciprocatory member, said duct having, when the machine is operating, an uncontrolled and continuously open inlet port and a controlled exhaust port, means for circulating liquid under pressure in said duct and adjacent said reciprocatory member to rapidly actuate it, a valve only controlling said exhaust port, and means actuated by said reciprocatory member for opening said valve upon movements of the reciprocatory member in one direction and for closing said valve upon movements of the reciprocatory member in the other direction.

2. A molding machine, comprising a unitary body formed with a cylinder, a reciprocatory member mounted in said cylinder, said body having a liquid duct therein opening adjacent said reciprocatory member, said duct having, when the machine is operating, an uncontrolled and continuously open inlet port and a controlled exhaust port, means for circulating liquid under pressure in said duct and adjacent said reciprocatory member to rapidly actuate it, a valve only controlling said exhaust port, and means carried by said reciprocatory member for automatically opening said valve upon a predetermined movement of said reciprocatory member in one direction and for automatically closing said valve upon a predetermined movement of the reciprocatory member in the other direction.

3. A molding machine, comprising a unitary body formed with a cylinder, a reciprocatory member mounted in said cylinder, said body having a liquid duct therein opening adjacent said reciprocatory member, said duct having, within the body an uncontrolled and continuously open inlet port and a controlled exhaust port, means for circulating liquid under pressure in said duct and adjacent said reciprocatory member to rapidly actuate it, a valve only controlling said exhaust port, and adjustable means carried by said reciprocatory member for automatically opening said valve upon a predetermined movement of said reciprocatory member in one direction and. for automatically closing said valve upon a predetermined movement of the reciprocatory memcuit for supplying liquid under pressure into said duct with the liquid alternately displacing said reciprocatory member and being displaced thereby, a valve only controlling said exhaust port, and means influenced by reverse movements of said reciprocatory member for alternately opening and closing said valve, said exhaust port being of a size when open, to only. accommodate the liquid being delivered through the inlet port plus that displaced by said reciprocatory member.

5. In a foundry jolt machine, in combination, a unitary body formed with a cylinder and a liquid duct in the body communicating with the lower end of the cylinder, a jolt piston vertically reciprocally mounted in said cylinder, a guide piston above the jolt piston and mounted to be vertically reciprocated thereby, a flask supporting table carried by the guide piston, said liquid duct being maintained filled with liquid and having, when the-machine is operating, an uncontrolled and continuously open inlet port and a controlled exhaust port adjacent the inlet port, a valve controlling only the exhaust port, means carried by said table for opening said valve upon a predetermined upward movement of the table and for closing said valve upon a predetermined downward movement of the table, and an oil pump having tubular connections extending both to said inlet port and to said exhaust port.

HARRISON E; FELLOWS. 

